Thermodynamic Origin Research Articles

Thermodynamic and Kinetic Effects on the Phase States of Amorphous Polymer and Organic Crystal Mixtures

We characterized the phase behavior of polystyrene and pyrene mixtures as a model binary system of amorphous polymer and crystallizing organic compound mixtures using the differential scanning calorimetry (DSC) technique. By employing various thermal processing procedures, we located the binodal temperatures (melting temperatures of pyrene crystals) and effective stability limit temperatures of pyrene crystallizations in the liquid–crystal two-phase domain. We observed that the binodal and effective stability limit temperatures are nearly insensitive to thermal processing procedures which indicates strong thermodynamic origins of these thermodynamic points. Remarkably, the effective stability limit curve shows the signature of an upper critical solution temperature which suggests that the pyrene crystallizations occur via liquid prenuclei domains signaling a hidden liquid–liquid phase domain in the liquid–crystal phase domain. We extracted the chemical compositions of polystyrene phases that have precipit...

Strain generation and energy-conversion mechanisms in lead-based and lead-free piezoceramics

Abstract

Tuning Free Energy by Backbone Conformational Entropy: A Strategy from Disordered Proteins

Tuning Free Energy by Backbone Conformational Entropy: A Strategy from Disordered Proteins

Thermodynamic origin of kappa distributions

Kappa distributions describe particle velocities and energies in collisionless particle systems such as space and astrophysical plasmas. While we understand the possible mechanisms that may generate these distributions in these plasmas, the thermodynamic origin of these distributions remains a challenge: Particle systems at thermal equilibrium are known to be described by the Maxwell-Boltzmann distribution, but it is unknown whether this distribution is unique or other distribution functions consistent with thermodynamics may exist. This paper resolves the thermodynamic origin of kappa distributions. For particle systems eventually reaching thermal equilibrium, we show: i) the existence of two thermodynamic integrals characterizing thermal equilibrium, corresponding to two independent intensive thermodynamic quantities, temperature and kappa index (parameter labelling kappa distributions); ii) the adaptation of Sackur-Tetrode entropy for kappa distributions with applications in solar wind plasma; iii) the pseudo-additivity rule of entropy; iv) that the most general, physically meaningful, distribution function that particle systems are stabilized into when reaching thermal equilibrium is the kappa distribution.

Formation and self-organization of void superlattices under irradiation: A phase field study

Self-organized patterns, realized in non-equilibrium processes, have been widely observed in physics and chemistry. As a powerful tool to create far-from-equilibrium environments, irradiation produces a variety of types of defects, which can self-organize through physical interactions and chemical reactions. Such a process becomes complicated especially when both thermodynamics and kinetics play critical roles in pattern formation. In this paper, we investigate the formation and self-organization mechanism of void superlattices in metals and alloys under irradiation through phase field modeling and simulations. For the first time, three different formation mechanisms of void superlattices are clearly distinguished according to their thermodynamic origin and reaction kinetics. It is found that the characteristic length and symmetry of an emerging superlattice is determined by the interplay of the thermodynamic driving force and the kinetic anisotropy of the system. Through parametric study, the effects of kinetic coefficients, such as atomic mobility and irradiation dose rate, on the nucleation, growth, coarsening, coalescence, and ordering of voids are systematically investigated. The theoretical model developed in this work may provide guidelines for designing desired self-organized microstructures under irradiation.

Electrochemical Oscillation in Li-Ion Batteries

Summary Two-phase reactions are prevalent in Li-ion batteries, whereas the underlying dynamics of phase separation in a real electrode still remain elusive, since numerous electrode particles constitute a formidably complex system for existing experimental techniques. Here we present an intriguing oscillatory phenomenon in the typical phase-separating electrode material Li 4 Ti 5 O 12 . During galvanostatic processes, the voltage oscillates due to the discrete nature of multi-particle phase-separating reactions, and the subtle oscillatory signals allow us to evaluate the fraction of actively phase-separating particles in real time. Through the analysis of oscillatory phenomena, we unveil the dependence of the active fraction on the depth of charge/discharge, cycling current, and working temperature, considerably deepening our understanding of the multi-particle phase-separation reaction. Moreover, it is the first time that electrochemical oscillations have been identified in rechargeable battery systems, opening up a new frontier for both theoretical and experimental researchers.

In Situ Acoustic Diagnostics of Particle-Binder Interactions in Battery Electrodes

Summary The high phase-transformation strain developed upon intercalation in the host particles of a composite battery electrode affects the polymeric binder network mechanically, deteriorating the electrode cycling performance. Here, electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) is used to demonstrate a new strain-accommodation mechanism, in high-strain NaFePO 4 /PVdF electrodes, via relaxation of the binder network surrounding the intercalation particles. Complete mechanical degradation of the polymer network occurs during long-term cycling of NaFePO 4 electrodes in aqueous solutions (hard and tough behavior). In contrast, in aprotic solutions, a softened binder easily accommodates the high transformation strain, ensuring excellent electrode cycling performance (soft and tough behavior). Quantification of the high-frequency viscoelastic properties of an operating composite electrode linked to the binder's fracture toughness ensures fast and facile screening of the optimal polymeric binder/electrolyte solution combinations. This methodology should be extremely important for optimization of cycling performance of Li-Si anodes undergoing huge volume changes during cycling.

Temperature-Dependent Lipid Extraction from Membranes by Boron Nitride Nanosheets.

Two-dimensional (2D) materials can mechanically insert into cell membranes and extract lipids out, thus leading to the destruction of cell integrity. On the one hand, the cytotoxicity of 2D materials can be harnessed in surface engineering to resist biofouling, and on the other hand, it causes great concern with in vivo biomedical applications ranging from drug delivery to nanoimaging. To understand the nature of this cytotoxic behavior and find strategies to control it, we performed molecular dynamics (MD) simulations on the lipid extraction of hexagonal boron nitride (BN) nanosheets from lipid membranes. Interestingly, we observed that the lipid extraction behavior suddenly disappears as temperature decreases. Structural analyses revealed that this temperature dependence is related to the lipid membrane phase transition, which was confirmed by an additional membrane model with phase state regulated by cholesterol. The potential of mean force calculation was adopted to clarify the thermodynamic origin of these results, which also indicates directions to adjust the lipid extraction behavior of nanomaterials. Overall, this work suggests that the cytotoxic mechanical interactions between 2D materials and cell membranes can be controlled by temperature and other factors which can induce phase transitions of lipid membranes and that the thermodynamic threshold of the lipid extraction varies for surfaces with different curvature. This work clarifies the thermodynamics in the lipid extraction phenomenon of 2D materials and indicates possible strategies to adjust the antibacterial performance or cytotoxicity of 2D materials.

Synthesis and Characterization of an Osmapentalene Derivative Containing a β-Agostic Os···H–C(sp3) Interaction

Treatment of cyclopropaosmapentalene (1) with EtC≡CEt in the presence of AgBF4 gave a new type of polycyclic metallaaromatic complex with a structure containing an sp3 carbon and a β-agostic Os···H–C(sp3) interaction. This result strongly supported our proposed intermediate in the reaction of cyclopropaosmapentalene 1 with alkynes that produced photothermal osmium carbolong complexes. When EtC≡CCOMe was used, the reaction gave a more thermally stable ketone-coordinated complex as the major product. The DFT study indicated that the difference in the two reactions is of thermodynamic origin.

A Multi-Step Approach to Assessing LIGO Test Mass Coatings

Photographs of the LIGO Gravitational Wave detector mirrors illuminated by the standing beam were analyzed with an astronomical software tool designed to identify stars within images, which extracted hundreds of thousands of point-like scatterers uniformly distributed across the mirror surface, likely distributed through the depth of the coating layers. The sheer number of the observed scatterers implies a fundamental, thermodynamic origin during deposition or processing. If identified as crystallites, these scatterers would be a possible source of the mirror dissipation and thermal noise, which limit the sensitivity of observatories to Gravitational Waves. In order to learn more about the composition and location of the detected scatterers, a feasibility study is underway to develop a method that determines the location of the scatterers by producing a complete mapping of scatterers within test samples, including their depth distribution, optical amplitude distribution, and lateral distribution. Also, research is underway to accurately identify future materials and/or coating methods that possess the largest possible mechanical quality factor (Q). Current efforts propose a new experimental approach that will more precisely measure the Q of coatings by depositing them onto 100 nm Silicon Nitride membranes.

Measurements of growing surface tension of amorphous\u2013amorphous interfaces on approaching the colloidal glass transition

There is mounting evidence indicating that relaxation dynamics in liquids approaching their glass transition not only become increasingly cooperative, but the relaxing regions also become more compact in shape. Of the many theories of the glass transition, only the random first-order theory—a thermodynamic framework—anticipates the surface tension of relaxing regions to play a role in deciding both their size and morphology. However, owing to the amorphous nature of the relaxing regions, even the identification of their interfaces has not been possible in experiments hitherto. Here, we devise a method to directly quantify the dynamics of amorphous–amorphous interfaces in bulk supercooled colloidal liquids. Our procedure also helped unveil a non-monotonic evolution in dynamical correlations with supercooling in bulk liquids. We measure the surface tension of the interfaces and show that it increases rapidly across the mode-coupling area fraction. Our experiments support a thermodynamic origin of the glass transition.

On the thermodynamic origin of metabolic scaling

The origin and shape of metabolic scaling has been controversial since Kleiber found that basal metabolic rate of animals seemed to vary as a power law of their body mass with exponent 3/4, instead of 2/3, as a surface-to-volume argument predicts. The universality of exponent 3/4 -claimed in terms of the fractal properties of the nutrient network- has recently been challenged according to empirical evidence that observed a wealth of robust exponents deviating from 3/4. Here we present a conceptually simple thermodynamic framework, where the dependence of metabolic rate with body mass emerges from a trade-off between the energy dissipated as heat and the energy efficiently used by the organism to maintain its metabolism. This balance tunes the shape of an additive model from which different effective scalings can be recovered as particular cases, thereby reconciling previously inconsistent empirical evidence in mammals, birds, insects and even plants under a unified framework. This model is biologically motivated, fits remarkably well the data, and also explains additional features such as the relation between energy lost as heat and mass, the role and influence of different climatic environments or the difference found between endotherms and ectotherms.

A new approach to precise thermodynamic characterization of hybridization properties of modified oligonucleotides: Comparative studies of deoxyribo- and glycine morpholine pentaadenines

The development of new derivatives and analogues of nucleic acids for the purposes of molecular biology, biotechnology, gene diagnostics, and medicine has been a hotspot for the last two decades. Methylenecarboxamide (glycine) morpholine oligomer analogues (gM) seem to be promising therapeutic candidates because of the ability to form sequence specific complexes with DNA and RNA. In this paper we describe new approaches to the determination of thermodynamic parameters for hybridization of tandem oligonucleotide complexes with the complementary template. It makes possible to determine changes in enthalpy and entropy corresponding to the binding of an individual oligomer with the template, and to the formation of cooperative contact at the helix-helix interface of two neighboring duplex fragments (in the nick). We have experimentally analyzed the series of model tandem complexes of different length at various oligomer concentrations, ionic strength, and pH. The analysis of thermodynamic parameters of complex formation for native and modified oligomers revealed higher Gibbs free energy values of hybridization and cooperative interaction of morpholine-containing complexes at the helix-helix interface under standard conditions (1M NaCl, pH7.2). Further comparative analysis of the hybridization properties of modified oligomers at ionic strength and pH allows us to determine the charge state of the morpholine backbone and the thermodynamic origin of the effects observed. It was found that the decrease in pH to 5.5 led to the protonation of internal morpholine nitrogens. The obtained results prove the veracity of the proposed model and the possibility to evaluate thermodynamic parameters of short native and modified oligomers with high accuracy.

On the effective Stefan-Boltzmann law and the thermodynamic origin of the initial radiation density in warm inflation

In this presentation, we are going to explain the thermodynamic origin of warm inflation scenarios by using the effetive Stefan-Boltzmann law. In the warm inflation scenarios, radiation always exists to avoid the graceful exit problem, for which the radiation energy density should be assumed to be finite at the starting point of the warm inflation. To find out the origin of the non-vanishing initial radiation energy density, we derive an effective Stefan-Boltzmann law by considering the non-vanishing trace of the total energy-momentum tensors. The effective Stefan-Boltzmann law successfully shows where the initial radiation energy density is thermodynamically originated from. And by using the above effective Stefan-Boltzmann law, we also study the cosmological scalar perturbation, and obtain the sufficient radiation energy density in order for GUT baryogenesis at the end of inflation. This proceeding is based on Ref. [1]

From the arrow of time in Badiali's quantum approach to the dynamic meaning of Riemann's hypothesis

The novelty of the Jean Pierre Badiali last scientific works stems to a quantum approach based on both (i) a return to the notion of trajectories (Feynman paths) and (ii) an irreversibility of the quantum transitions. These iconoclastic choices find again the Hilbertian and the von Neumann algebraic point of view by dealing statistics over loops. This approach confers an external thermodynamic origin to the notion of a quantum unit of time (Rovelli Connes' thermal time). This notion, basis for quantization, appears herein as a mere criterion of parting between the quantum regime and the thermodynamic regime. The purpose of this note is to unfold the content of the last five years of scientific exchanges aiming to link in a coherent scheme the Jean Pierre's choices and works, and the works of the authors of this note based on hyperbolic geodesics and the associated role of Riemann zeta functions. While these options do not unveil any contradictions, nevertheless they give birth to an intrinsic arrow of time different from the thermal time. The question of the physical meaning of Riemann hypothesis as the basis of quantum mechanics, which was at the heart of our last exchanges, is the backbone of this note.

The thermodynamic origin of compositional nanoheterogeneity in glasses

The thermodynamic origin of compositional nanoheterogeneity in glasses

Common mechanism of thermodynamic and mechanical origin for ageing and crystallization of glasses

The glassy state is known to undergo slow structural relaxation, where the system progressively explores lower free-energy minima which are either amorphous (ageing) or crystalline (devitrification). Recently, there is growing interest in the unusual intermittent collective displacements of a large number of particles known as ‘avalanches’. However, their structural origin and dynamics are yet to be fully addressed. Here, we study hard-sphere glasses which either crystallize or age depending on the degree of size polydispersity, and show that a small number of particles are thermodynamically driven to rearrange in regions of low density and bond orientational order. This causes a transient loss of mechanical equilibrium which facilitates a large cascade of motion. Combined with previously identified phenomenology, we have a complete kinetic pathway for structural change which is common to both ageing and crystallization. Furthermore, this suggests that transient force balance is what distinguishes glasses from supercooled liquids.

Optical scattering measurements and implications on thermal noise in Gravitational Wave detectors test-mass coatings

Photographs of the LIGO Gravitational Wave detector mirrors illuminated by the standing beam were analyzed with an astronomical software tool designed to identify stars within images, which extracted hundreds of thousands of point-like scatterers uniformly distributed across the mirror surface, likely distributed through the depth of the coating layers. The sheer number of the observed scatterers implies a fundamental, thermodynamic origin during deposition or processing. These scatterers are a possible source of the mirror dissipation and thermal noise foreseen by V. Braginsky and Y. Levin, which limits the sensitivity of observatories to Gravitational Waves. This study may point the way towards the production of mirrors with reduced thermal noise and an increased detection range.

Thermodynamic origin of the null energy condition

We derive the classical null energy condition, understood as a constraint on the Ricci tensor, from the second law of thermodynamics applied locally to Bekenstein-Hawking entropy associated with patches of null congruences. The derivation provides evidence that the null energy condition, which has usually been regarded as a condition on matter, is fundamentally a property of gravity.

Thermodynamic origin and graphical methods of phase theory

Thermodynamics is often considered difficult to understand due to extensive use of mathematics. In the present paper, a graphical approach will be used to explain the origin of phase diagrams starting from the fundamental equation of thermodynamics dU = Tds − Pdv defined by J.W. Gibbs. The characteristic variables of this equation are the specific entropy s and the specific volume v, which lead in a straightforward way to s-v phase diagrams. It will be demonstrated through monotonicity of the internal energy curves of the different phases of the system and graphical Legendre transformations how pressure-entropy (P-s) and temperature-volume (T-v) phase diagrams are linked to s-v phase diagrams and how the latter two phase diagrams are related to pressure-temperature (P-T) phase diagrams.